1. Field of the Invention
The present invention relates to a curved window glass panel and a method of installing a curved window glass panel on an attachment frame on an automobile body by pressing the curved window glass panel against the attachment frame, and more particularly to a curved window glass panel, such as a rear window glass panel, which has a pair of end portions bent over opposite sides of an automobile body, and a method of installing such a curved window glass panel reliably on an attachment frame without the danger of water leakage through the attached edge of the curved window glass panel.
2. Description of the Related Art
Recent automobile design trends include a rear window panel as shown in FIG. 6 of the accompanying drawings. As shown in FIG. 6, a curved window glass panel 12 has a pair of large end portions 12a bent forward over opposite sides 11a of an automobile body through a large angle. The curved window glass panel 12 has a peripheral edge coated with a decorative ceramic color layer 12b.
FIG. 7A of the accompanying drawings shows a curved window glass panel 13 having a pair of end portions 13a each bent through an angle .alpha. of 130.degree. or greater. To install the curved window glass panel 13 on an attachment frame, a sealer is disposed on and projects from the inner peripheral edge of the curved window glass panel 13, and the curved window glass panel 13 is pressed against the attachment frame through the sealer, so that the curved window glass panel 13 is bonded to the attachment frame without the danger of water leakage.
FIG. 7B of the accompanying drawings illustrates a curved window glass panel 14 having a pair of end portions 14a each bent through an angle .alpha. ranging from 90.degree. to 130.degree.. Since a more complex process is required to shape and bend the curved window glass panel 14 than the curved window glass panel 13 shown in FIG. 7A and the attachment frame for installing the curved window glass panel 14 thereon also requires more complicated machining than the attachment frame for installing the curved window glass panel 13, it is relatively difficult to achieve predetermined dimensional accuracy for the curved window glass panel 14 and the attachment frame for installing same thereon.
As shown in FIG. 8 of the accompanying drawings, each of the bent end portions 12a of the curved window glass panel 12 shown in FIG. 6 is pressed against an attachment frame 10 while the bent end portion 12a is being inclined to the direction indicated by the arrow A in which the curved window glass panel 12 moves for installation. At this time, a sealer 15 projecting from the inner surface of the peripheral edge of the curved window glass panel 12 has a side face held against the attachment frame 10 because the curved window glass panel 12 moves in the direction A for installation. Therefore, when the curved window glass panel 12 is subjected to lateral forces, the sealer 15 tends to be damaged or cause water leakage by being laterally bent or sheared.
More sharply curved window glass panels are liable to be installed less accurately owing to relatively low dimensional accuracy. When they are laterally displaced due to poor installation accuracy, there may be developed a step or a gap between the automobile body and the curved window panel, impairing the appearance of the automobile body. Such a positional displacement of the curved window glass panel is also responsible for water leakage through the sealer. The curved window glass panels that are positionally displaced with respect to the automobile body lose their commercial values in terms of design and function.
One customary practice to eliminate the above problems has been to manually adjust a curved window glass panel and an attachment frame on which it is to be installed, and then manually install the curved window glass panel on the attachment frame while laterally balancing the curved window glass panel.
If a curved window glass panel is installed on an attachment frame with an automatic installing machine, then it is necessary to detect manufacturing errors of the curved window glass panel and the attachment frame, and correct the installation process based on the detected manufacturing errors. The automatic installing machine is required to be controlled in a manner depending on the type of window glass panel, such as a rear window glass panel, that is to be installed. Accordingly, a dedicated installation line having dedicated automatic installing machines is needed, and a large expenditure of equipment investments is unavoidable for establishing such a dedicated installation line.